0740 Quality of Life in Phase 3, Placebo-Controlled, Double-Blind, Randomized Withdrawal Study of JZP-258 in Adults with Narcolepsy with Cataplexy

Abstract Introduction Narcolepsy negatively impacts health-related quality of life (HRQoL). Sodium oxybate is a standard of care for the treatment of cataplexy and excessive daytime sleepiness in narcolepsy. JZP-258 is an oxybate product candidate with 92% less sodium. Efficacy and safety of JZP-258 were established in a double-blind randomized withdrawal study in adults with narcolepsy with cataplexy. Methods Participants 18-70 years of age began JZP-258 treatment during a 12-week, open-label, optimized treatment and titration period, followed by a 2-week stable-dose period (SDP). Participants were then randomized to receive placebo or continue JZP-258 treatment during a 2-week, double-blind, randomized withdrawal period (DBRWP). HRQoL assessments included the 36-Item Short Form Health Survey Version 2 (SF-36) and 5-level EuroQoL 5-Dimensions Self-Report Questionnaire (EQ-5D-5L). Results 201 participants enrolled; 134 were randomized and received at least 1 dose of double-blind study medication (efficacy population; placebo, n=65; JZP-258, n=69). Decreased scores (worsening) were observed in participants randomized to placebo compared with participants randomized to continue JZP-258 treatment for the SF-36 physical component summary (median [Q1, Q3], −1.92 [−3.46, 1.73] for placebo and −0.03 [−2.07, 2.41] for JZP-258; nominal P=0.02), SF-36 mental component summary (−1.92 [−6.28, 1.34] for placebo and 1.55 [−1.88, 3.78] for JZP-258; nominal P=0.03), and EQ-5D-5L visual analog scale (−5.00 [−10.0, 5.00] for placebo and 0 [0, 5.00] for JZP-258; nominal P=0.01). No change was observed in the EQ-5D-5L crosswalk index (0 [−0.05, 0.03] for placebo and 0 [−0.01, 0.03] for JZP-258; nominal P=0.39). The overall safety profile of JZP-258 was similar to sodium oxybate. Conclusion HRQoL worsened in those randomized to placebo during DBRWP but remained stable in participants who continued JZP-258 treatment. Support Jazz Pharmaceuticals